1. Field of the Invention
The present invention relates to small internal combustion engines of the type used for lawn mowers, lawn and garden tractors, snow throwers and other implements, or small sport vehicles. Particularly, the present invention relates to a priming system to aid in starting such engines.
2. Description of the Related Art
Small internal combustion engines typically include a carburetor which mixes liquid fuel with atmospheric air drawn through the carburetor to provide an air/fuel combustion mixture to the engine. One type of carburetor commonly used in small engines includes a throat with a venturi through which air is drawn, and into which fuel is drawn for mixing with the intake air. A fuel bowl is disposed beneath the throat in which a quantity of liquid fuel is contained. A float valve in the fuel bowl meters the supply of fuel into the fuel bowl from the main fuel tank as necessary as the fuel in the fuel bowl is consumed.
Additionally, such carburetors typically include a manually operable priming feature, such as a flexible priming bulb which is depressed by an operator to pressurize the air space above the fuel in the fuel bowl, thereby forcing a quantity of priming fuel into the carburetor throat for mixing with the intake air which is drawn into the carburetor. The priming fuel is in excess of the amount of fuel which is normally supplied for mixing with the intake air to form a combustion mixture, such that a rich air/fuel mixture is initially supplied to the engine to aid in engine starting. After the engine starts, the priming fuel is consumed, and mixing of the air/fuel mixture is thereafter controlled by the fuel metering system of the carburetor during running of the engine.
The foregoing priming feature for carburetors requires an operator to manually press the flexible priming bulb at the location of the carburetor in order to prime the engine. Although remote priming devices which utilize a cable operably connected between the handle of an implement and the flexible priming bulb of the carburetor have been devised, such devices typically require multiple actuations thereof by an operator in order to build sufficient air pressure within the carburetor bowl to properly pressurize same.
Additionally, repeated actuation of such priming mechanisms when the engine is already in a warm condition, such as during warm engine re-starts, may provide an unnecessarily rich fuel/air mixture to the engine which could flood the engine.
It is desirable to provide a priming system for use with carburetors of small internal combustion engines which is an improvement over the foregoing.